Abstract
A new and versatile class of metal-organic materials (MOMs) with augmented lonsdaleite-e (ion-e-a) topology is presented herein. This family of ion-e nets are built by pillaring of hexagonal two-dimensional kagome (kag) lattices constructed from well-known [Zn-2(CO2R)(4)] paddlewheel molecular building blocks (MBBs) connected by 1,3-benzenedicarboxylate (bdc(2-)) linkers. The pillars are [Cr-3(mu(3)-O)(RCO2)](6) trigonal prismatic primary MBBs decorated by six pyridyl moieties (tp-PMBB-1). The threefold symmetry (D-3h) of tp-PMBB-1 is complementary with the alternating orientation of the axial sites of the paddlewheel MBBs and enables triple cross-linking of the kag layers by each pillar. These MOMs represent the first examples of axial-to-axial pillared undulating kag layers, and they are readily fine-tuned because the bdc(2-) moieties can be varied at their 5-position without changing the overall structure. This Ion-e platform possesses functionalized hexagonal channels since the kag lattices are necessarily eclipsed. The effects of the substituent at the 5-positions of the bdc(2-) linkers upon gas adsorption, particularly the heats of adsorption of carbon dioxide and methane, were studied.